1. Field of the Invention
The present invention relates to an inspection apparatus and an inspection method, and more particularly to conducting an inspection of an object to be measured by using a terahertz wave.
2. Description of the Related Art
The terahertz wave refers to an electromagnetic wave having any frequency band within the range of 0.03 THz to 30 THz. In the terahertz wave band, there are characteristic absorptions derived from structures and states of living body molecules and other various substances. Inspection technologies for conducting nondestructive analysis and identification of substances taking advantage of such characteristics have been developed. Furthermore, application to a safe imaging technology in place of X-rays and a high-speed communication technology may be expected.
Regarding such imaging technology, an apparatus which acquires information of an object to be measured in a depth direction has been developed. This apparatus derives a spike-shaped time waveform by conducting deconvolution based on a perfect reflection waveform of a terahertz wave with respect to a terahertz reflection waveform from the object to be measured. Here, an example of imaging in the inside of FLOPPY (registered trade mark) is demonstrated, wherein an improvement in resolution is intended by determining a refractive index interface through the use of the spike-shaped time waveform. A form in which a terahertz wave measured through replacement with a mirror or other substances that conduct reflection while a loss is substantially zero is used as a perfect reflection waveform of terahertz wave is disclosed in FIG. 2 of Japanese Patent Laid-Open No. 11-108845 (Corresponding to U.S. Pat. No. 6,078,047, hereinafter Patent Document 1).